JPS63122116A - Manufacture of modulated doped superlattice structure - Google Patents

Abstract

PURPOSE:To form P-type and N-type modulated doped superlattice structures in one superlattice forming step by simultaneously performing P-type and N-type modulated dopings on a substrate formed stereoscopically by an MBE device having two types of P-type and N-type impurity sources having different incident directions and at least two types of material sources. CONSTITUTION:A P-type dopant inlet 1, a silicon material inlet 2 for SiH2, a germanium material inlet 3 for GeH4, and N-type dopant inlet 4 are provided in an MEB device for a modulated doped superlattice structure. A P-type dopant is supplied from a direction 21 while supplying silicon in a direction 22, and an N-type dopant is supplied from a direction 23 into a chamber while supplying the silicon and the germanium from a direction 22. At this time, P-type and N-type impurities are simultaneously charged to a section 24, but since no N-type impurity is incident to the section 24, it is doped in the P-type, and since a P-type impurity is not incident to a section 26, it is doped in N-type.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing P-type and n-type modulated doping superlattice structures.

[Conventional technology]

A modulated doping superlattice structure was proposed by ZSaki et al. in 1970, and was realized in the GaA3/AtXGa 1-XA5t system by Dingle et al. in 1978. Since then, there have been many reports, but S i / G
The existence of two-dimensional electron gas and two-dimensional hole gas has also been confirmed in eJ X 311-X fA and the like.

[Problem that the invention seeks to solve]

However, since modulation doping can only be performed during crystal growth, that is, during the creation of a superlattice structure, in order to perform modulation doping of P-type and n-type on the same substrate, it is necessary to conduct the crystal at least twice. A growing process is required. A
In the L x Ga 1-X A a system, the mobility of holes is small, so P-type modulation doping has not received much attention, but materials such as the 8l-Ge system, in which both electron and hole mobilities are high to some extent, Now, in the modulation doping superlattice structure, both Pfi and n-type have great utility value, that is, it is possible to create an integrated circuit that operates at high speed and with low power consumption using complementary modulation doping superlattice transistors. But 2
Forming a superlattice structure over multiple times not only makes it difficult to form complementary transistors, but also puts a heavy burden on superlattice structure formation with low throughput. The present invention is intended to solve these problems, and its purpose is to:
The object of the present invention is to provide a method for forming P-type and n-type modulation doped superlattice structures in one superlattice structure formation process.

[Means for solving problems]

The method for manufacturing a modulated doping superlattice structure of the present invention is performed using an MBE apparatus equipped with two types of impurity sources, P-type and n-type, with different incident directions, and at least two types of raw material sources. Using a substrate, a P-type modulation-doped superlattice structure part and an n-type modulation-doping superlattice structure part are created in one superlattice structure forming process. In other words, by utilizing the straightness of molecular beams, even if P-type and N-type impurities are simultaneously introduced into a high vacuum chamber, each impurity will not be taken in at the same time. By separating the positions and processing the substrate into a shape that prevents two types of molecular beams from being incident at the same time.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples. FIG. 1 is a schematic diagram of an MBK apparatus for carrying out the method of manufacturing a modulation-doped superlattice structure of the present invention. Portions such as the high vacuum evacuation system 1 analysis device and wafer introduction system are omitted. In addition, in the example, MB of the 5i-Ge gas source
Regarding Fi, we will discuss MBK with a solid source using the AtxGai-xAa system or an evaporation cell, as well as an ionization device in each cell, as described by J, O', Bean et al. (J.

vac Soc Tech 20 157 19
It is clear that the manufacturing method of the present invention can also be used with an ion source using a neutral particle trap such as 82). 1 is the introduction port for P-type dopant, 2 is SiH4
3 is a germanium raw material inlet such as G e H4, and 4 is an n-type dopant inlet. These raw material gases are heated in the pyrolysis chambers 5, 6, and 7.8 as necessary, and then introduced into the high vacuum chamber 16 from the gas outlets 9.10, 11, and 12. ing.

13 is a silicon substrate, 14 is a susceptor, and 15 is an exhaust port connected to a high vacuum exhaust system.

What should be noted in particular is that the P-type dopant outlet and the N-type dopant outlet are provided in different directions with respect to the silicon substrate. Using this device to create a modulation doping superlattice structure This section explains how to do this.

Figure 2 shows P type and n type on a three-dimensionally processed silicon substrate.
This is intended to briefly explain the method of forming a type of modulation doped superlattice structure. Reference numeral 21 indicates the direction of incidence of the P-type dopant in the MBK device, 22 indicates the direction of incidence of silicon and germanium, and 23 indicates the direction of incidence of the n-type dopant. 27 is a sectional view of a silicon substrate processed into a well shape or a stripe shape. Si/
In the modulation-doped superlattice structure of the G e x S i l-x system, the G e x S i L-x layer or the Si
A dopant is introduced into the layer to form a two-dimensional electron gas and a two-dimensional hole gas. When growing the non-doped layer 81, only silicon is supplied from the direction 22. Ge, s
In the growth of 1l-xFIJ, n-type doping is performed from the direction 22 when forming the silicon layer, but while silicon is supplied from the direction 22, P-type dopant is supplied from the direction 21, and silicon and germanium are supplied. Shinaka 2
NG dopant is introduced into the chamber from direction 3. At this time, P-type and n-type impurities are incorporated into the 24 part at the same time, but the 25 part is doped with P type because no n-type impurity is incident on it, and the 260 part is doped with P-type impurities. Therefore, it is doped to be n-type.

Therefore, 1 forming a normal modulation-doped superlattice structure
It is possible to form modulation-doped superlattice structures of both P and n types in just one step. It is also possible to control each doping amount independently.

Although FIG. 3 shows an example of processing a substrate to obtain the same effect as in FIG. 2 by tilting the substrate, it is obvious that various other processing methods are possible.

FIG. 4 schematically depicts temporal changes in the molecules am of silicon, germanium, P9 dopant, and n-type dopant when forming a modulation doping superlattice structure.

〔Effect of the invention〕

As described above, according to the present invention, in an MBK apparatus equipped with two types of impurity sources, P-type and n-type, with different incident directions, and at least two types of raw material sources, a three-dimensionally processed substrate can be On the other hand, since P-type and n-type modulation doping can be performed simultaneously, the P-type and n-type modulation doping can be superimposed, which is necessary to manufacture complementary transistors using two-dimensional electron gas and two-dimensional hole gas. The lattice structure has one stop + 4- Knee h← d5 〒 μm-A Yu; (
! -To '1 ψ L ^;-Oshi -Out η too!
Doping with impurities can only be performed during the creation of the knee lattice structure. Therefore, the ability to perform P-type and n-type modulation doping simultaneously can be said to be a necessary condition for the method of the present invention in order to create complementary transistors.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an MBE apparatus necessary for manufacturing the modulation-doped superlattice of the present invention. FIG. 2 is a sectional view of a silicon substrate subjected to modulation doping according to the manufacturing method of the present invention. FIG. 3 is a cross-sectional view of a silicon substrate for manufacturing a modulated doping superlattice structure according to the present invention. FIG. 4 is a diagram schematically depicting temporal changes in each molecular dose during the production of a modulated doping superlattice structure. Interviewer: Seiko Epson stock No. 412 ÷ Kki 717
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-(-/j-%-ζ:”d@/Q++ Creating the ITGrJ structure has very poor throughput and requires a super agent (one other person) Figure 3

Claims (1)

[Claims] In an MBE apparatus equipped with two types of impurity sources, P-type and n-type, with different incident directions, and at least two types of raw material sources,
A method for manufacturing a modulation-doped superlattice structure, characterized in that a P-type portion and an N-type portion are simultaneously formed using a three-dimensionally processed substrate.